Boron Dynamics in Agricultural Soils of the Cerrado: Study on Sources, Doses and Leaching

Abstract

The objectives of this study were: to evaluate the leaching potential of B in a Latossolo Vermelho-Amarelo (Oxisol) as a function of sources and doses of this micronutrient; among the sources tested (boric acid, ulexite and the commercial source H2 Boro), to determine the one with the lowest leaching potential; to evaluate leaching losses at different doses in each soil layer evaluated; and to identify chemical and physical variables of soils that influence B leaching. For that, two experiments were conducted in a greenhouse. The first one tested B leaching in the soil, with the three sources under study and five doses of B (0; 12; 24; 36; and 48 kg ha-1), whereas the second experiment evaluated the influence of soil physical and chemical attributes on B leaching using soils randomly collected in 22 localities in southeastern Goiás, Brazil. Regardless of the dose applied, ulexite led to the lowest soluble B content in the profile of the analyzed soils and also in the leachate. Boric acid was the only source that showed a different behavior in relation to B content in the different soil layers and in the leachate. In the soil layer from 21 to 30 cm, ulexite is the source with the lowest soluble B content. The behaviors of the more soluble sources, in this case boric acid and H2 Boro (H2 Agrosciences - Monoethanolamine borate), regardless of the dose, are very similar, being highly leachable in the profile of the Oxisol used. Soils with clayey texture and higher values of H+Al and CEC were able to retain higher B contents in the upper portion their profiles (layers from 0 to 10 cm and 11 to 20 cm), but soils with sandy texture and higher values of sum of bases showed greater B losses by leaching.

Leachate characteristics, dry matter yield of Urochloa decumbens and properties of two contrasting soils irrigated with sludgewater in columns

“…However, retention occurred in both soils suggesting that the B added in sludgewater was occluded in secondary minerals or by the organic matter fraction. Studies in the literature confirm that B retention in soils is significantly influenced by the source and that plants respond directly to the activity of B in soil solution (da Silva et al., 2022; Goldberg, 1997; Steiner & Lana, 2013). This is further evidenced by the lack of significant differences in tissue concentration of B in all sludgewater treatments on the clay.…”

Efeito da aplicação boratada em diferentes estádios fenológicos na qualidade fisiológica de sementes de soja

“…A carência nutricional é comumente observada na produção agrícola, com ênfase aos micronutrientes, a exemplo do boro (B), oriundos no solo via decomposição de material orgânico (Silva et al, 2021). Apesar da grande importância do B na nutrição de plantas, as informações referentes à adubação boratada ainda são escassas, de modo a restringir a recomendação de adubação boratada adequada à obtenção de êxito produtivo .…”